The invention relates to medical catheters, and, more particularly, to drainage catheters with distal anchoring mechanisms.
Some medical treatments involve the use of a medical catheter with a distal anchor that retains the catheter in position in the body of a patient. Some treatments use a drainage catheter. For example, procedures for the suprapubic catheterization of the bladder drain the bladder after surgery or when an obstruction plugs the genitourinary system. Percutaneously inserted catheters can also drain the kidneys, biliary system, abscesses, other sites of fluid collection and other viscera. As an alternative to providing drainage, percutaneously inserted catheters can introduce substances into the patient""s body such a fluids introduced through gastrostomy feeding tubes.
Since body movements can inadvertently lead to catheter displacement, various anchoring mechanisms have been developed. For example, a Foley bladder catheter includes an inflatable balloon at the distal end, an inflation channel in the walls of the catheter, an external supply of inflation fluid connected to the channel and a valve to keep the fluid in place and the balloon inflated.
Alternatively, the distal end of the catheter can include a xe2x80x9cpigtail loopxe2x80x9d formed from a flexible tube. Typically, the pigtail loop is preformed from a shape-memory material. For introduction into a patient, a physician inserts a stiff cannula or stylet into the catheter lumen to straighten the pigtail loop. The distal end of the flexible tube returns to the pigtail configuration after the physician removes the cannula. In some cases, return to the pigtail configuration may be aided or secured by the use of a suture thread that extends through draw ports at two spaced positions on the flexible tube. These draw ports move toward each other when the physician removes the cannula. The physician can then take up slack and secure the pigtail by applying tension to the suture thread. To remove the catheter, the physician can reverse the above procedures.
Other anchor mechanisms include malecots with xe2x80x9cwingsxe2x80x9d or xe2x80x9carmsxe2x80x9d in a distal portion of the catheter wall. The application of force to a distal tip of the catheter can expand the wings, and the wings extend outward protruding radially to create an anchor for the catheter. The force can be applied by pulling on a suture string or a rod extending through the lumen of the catheter. Alternatively, the wings of the malecot can be formed from a shape-memory material with a naturally protruding configuration, and a stylet is used to push the distal end of the catheter and collapse the malecot.
A catheter according to the invention does not require the use of a shape-memory material, a stylet, or dual tubes for collapsing an anchor mechanism. Also, catheters according to the invention do not require a physician to manipulate separately two different tension members (e.g., two sutures) extending through the catheter lumen.
A catheter of the present invention includes one or more tension members to pull on one or more arms of a dilating member to collapse the dilating member. The tension members, in cooperation with a lock member, can secure the dilating member in a collapsed state. A single tension control member (located, for example, at the proximal end of the catheter), and operable with one hand, can simultaneously produce opposite changes in tension in two tension members attached to a dilating member.
Catheters according to the invention do not require stylets. A physician can collapse and secure the dilating member, for insertion or removal of the catheter, by applying tension (e.g., a pulling force) to a tension member. Further, catheters of the invention can include a tension control member that cooperatively controls the tension in two separate tension members to permit a physician securely and controllably to expand and collapse the dilating member with the use of just one hand.
In general, in one aspect, the invention features a medical device for draining fluid from the body of a patient. The device comprises an elongate member that defines a lumen and includes a proximal end and a distal portion. The device further comprises a dilating member disposed in the distal portion of the elongate member. The dilating member comprises a plurality of arms movable from a collapsed state to an expanded state in which the arms protrude radially to anchor the device within the body of the patient. The device further comprises a tension member extending through the lumen to the dilating member and coupled to the plurality of arms such that the application of tension to the tension member causes the arms to move to the collapsed state thereby permitting insertion and removal of the device into and from the body of the patient.
Embodiments of this aspect of the invention can include the following features. The device can include a second tension member extending through the lumen to the dilating member. The second tension member couples to a distal end of at least one of the arms such that application of tension to the second tension member causes the arms to move to the expanded state.
The device can further include a tension control member disposed at the proximal end of the elongate member, movable in at least a first direction and a second direction. The tension control member is coupled to the tension members such that movement of the tension control member in the first direction causes an increase in tension of the tension member and a decrease in tension of the second tension member that causes the arms to move to the collapsed state. Movement of the tension control member in the second direction causes an increase in tension of the second tension member and a decrease in tension of the tension member that causes the arms to move to the expanded state.
In some embodiments, the tension members comprise a flexible material. In some embodiments, the tension control member is slidably coupled to the elongate member to permit movement in proximal and distal directions. In other embodiments, the tension control member is rotatably coupled to the elongate member to permit clockwise and counterclockwise rotational movement around a longitudinal axis of the elongate member. In some embodiments, the tension control member is lockable to fix the tensions in the tension members to secure the arms when in the collapsed state, and when in the expanded state.
In general, in another aspect, the invention features a device with a tension control member that cooperatively adjusts the tension in at least two tension members. The device comprises an elongate member that defines a lumen and includes a proximal end and a distal portion. A tension control member is disposed at the proximal end of the elongate member and movable in at least a first direction and a second direction. A first tension member couples to the tension control member at a first site and extends through the lumen to the distal portion. A second tension member couples to the tension control member at a second site and extends through the lumen to the distal portion.
Movement of the tension control member in the first direction causes an increase in tension of the first tension member and a decrease in tension of the second tension member. Conversely, movement of the tension control member in the second direction causes an increase in tension of the second tension member and a decrease in tension of the first tension member.
Embodiments of this aspect of the invention can include the following features. The first and second tension members can comprise a flexible material. The tension control member can be slidably coupled to the elongate member to permit movement in proximal and distal directions. In other embodiments, the tension control member is rotatably coupled to the elongate member to permit clockwise and counterclockwise rotational movement around a longitudinal axis of the elongate member.
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.